#include<stdio.h>
#include<time.h>

int fib(int n){

    if(n<2)
        return 1;
    return fib(n-1)+fib(n-2);
}

int main()
{
    int n;
    while(1==scanf("%d",&n))
        printf("%d\n",fib(n));

    return 0;
}
